Case 7- infection clinical

Question 1

Rhinovirus

Answer 1

Causes 80% of colds, grows in the nasal cavities and upper respiratory tract. Lots of different serotypes. Several serotypes circulate simultaneously for several years then they are displaced so we are unable to develop resistance. It is transmitted through the respiratory route so air droplets, contaminated surfaces and hand to mouth.

Question 2

Adenovirus

Answer 2

Causes by non-enveloped double stranded DNA viruses. It was first isolated from human adenoids. It is responsible for 5-10% of respiratory viral infections. 51 different serotypes which have been classified into 7 species (A-G). Outbreaks in densely populated areas with a high population such as barracks and hostels.

Question 3

Adenovirus symptoms

Answer 3

Cold like symptom, Pharyngitis, Bronchitis, Pneumonia, Diarrhoea, Fever and Pink eye

Question 4

Adenovirus vaccine

Answer 4

There is vaccination in new military recruits to reduce outbreaks of infection

Question 5

Diagnosing Adenovirus

Answer 5

PCR. Virus isolation from clinical samples, immunological techniques will allow you to identify the specific subtype of the adenovirus.

Question 6

Coronavirus

Answer 6

Coronaviruses are enveloped, single stranded RNA viruses. Two strains cause between 2-10% of common cold cases, normally mild infections. There is an incubation period of three days before symptoms show.

Question 7

Coronavirus symptoms

Answer 7

Malaise, nasal discharge, no fever, sore throat

Question 8

SARS

Answer 8

SARS originated from a reservoir Rat/Civet cat. It spread throughout South-East Asia, the epicentre was Hong Kong. There have been no cases since 2004. Contained by public health measures. It also spread to Canada as there is lots of travel between HK and Canada.

Question 9

Diagnosing coronavirus

Answer 9

Through RT-PCR (reverse transcriptase) from swabs

Question 10

MERS

Answer 10

Originated in the middle east, majority of cases are in saudi arabia

Question 11

Paramoxyvirus

Answer 11

It is a respiratory syncytial virus (RSV) which is the most common causative agent of bronchiolitis in infants. Paramyxovirus is an enveloped, single-stranded RNA virus. It may cause death in the very young, elderly and immune-compressed. Peaks in the winter.

Question 12

Paramoxyvirus (measles, mumps) symptoms

Answer 12

Incubation period of 5 days, the illness is similar to the common cold (in most cases). Some children under a year old will show signs of pneumonia/bronchiolitis. Re-infection is common. 90% of infants get infected by 2. Only affects infants

Question 13

Paramoxyvirus diagnosis

Answer 13

Antigen testing/ cell culture/ RT-PCR

Question 14

RSV prevention

Answer 14

Palivizumab monoclonal antibodies are given prophylactically to susceptible infants, using effective hand hygiene.

Question 15

What does influenzas cause

Answer 15

Regular pandemics and epidemics. You get a lot of variation year on year

Question 16

Influenza virus

Answer 16

Influenza virus are orthomyxoviruses, this means that they are enveloped negative RNA viruses with segmented genomes. The transmission is via the respiratory route, there is a 2-3 day incubation period before you see any symptoms. The virus replicates in epithelial cells of the respiratory tract, the cilia are destroyed. Short lived disease

Question 17

Influenza symptoms

Answer 17

Abrupt onset, Shivering, Malaise, Headache, Aching limbs and back, High fever (39 degrees). Many of the symptoms are due to the cytokine storm released by infected cells.

Question 18

When is infleunza dangerous

Answer 18

Potentially dangerous for the very young/elderly. Can be associated with secondary infections like pneumonia

Question 19

Influenza virus structure

Answer 19

The Genome is composed of 8 x RNA segments which are surrounded by matrix proteins. On the genome is NP proteins. On the surface of the virus you have the Neuraminidase (N) proteins. The Neuraminidase is antigenic and aids release from infected cells, so it can invade other cells. Another surface protein they have is Haemagglutinin (H), it is antigenic and binds to target cell surfaces.

Question 20

What defines the 3 influenza types

Answer 20

By the serology of the internal matrix-proteins and N-proteins

Question 21

Influenza A

Answer 21

Linked to epidemics and pandemics. It infects animals (pigs and birds). Major changes in these antigens can occur, this is dangerous as there may not be widespread immunity to this variation.

Question 22

How you classify influenza A

Answer 22

It is categorised based on the antigenic relationship of external spike proteins e,g., H1NI and H5N1. There are 7 different types of H-Haemagglutinin (H1-H7). There are 9 different types of N-Neuraminidase (N1-N9).

Question 23

Influenza B

Answer 23

Causes milder epidemics

Question 24

Why does flu give rise to pandemics?

Answer 24

Influenza experiences genetic variability that gives rise to antigenic changes that evade previous immunity

Question 25

Antigenic drift

Answer 25

Minor changes in H and N proteins due to random mutations/substitutions. This because virus replication is not tightly controlled so errors happen regularly. After 4 years you will no longer have immunity to the virus due to the accumulation of mutations from drift variants. Results in influenza A and B epidemics

Question 26

Antigenic shift

Answer 26

When the influenza A virus acquires new H and N proteins. As the change is so abrupt people quickly loose their immunity and it can result in Influenza A pandemics. This occurs every 10-20 years i.e. Swine flu.

Question 27

How does antigenic shift arise?

Answer 27

Antigenic shift occurs when two different flu viruses infect the same cell and genetic re-assortment occurs. The net result is a new virus with different H and N proteins. This can happen in birds or pigs and then be transferred to humans. Genetic segments can jump from cell to cell and between different species to create a completely different virus. Pandemics outbreaks of flu occur after the emergence of shifted strains.

Question 28

Influenza treatment

Answer 28

Neuraminidase inhibitors like Tamiflu (oseltamivir) and Relenza (zanmivir). Only used in high risk groups as its not very effective but is expensive.

Question 29

Influenza vaccination

Answer 29

For children it’s a live vaccine given nasally. For adults they mainly use inactivated vaccines containing purified H and N subunits. It is re-formulated at intervals to match prevalent strain. Its about 30-60% effective in adults, also reduces complications.

Question 30

Endemic

Answer 30

A disease that is always prevalent in certain population or region, i.e. Malaria in the topics

Question 31

Epidemic

Answer 31

An outbreak of a contagious disease that spreads rapidly and widely

Question 32

Pandemic

Answer 32

An epidemic over a wide geographic area and affecting a large proportion of the population, i.e. COVID-19

Question 33

Spanish flu

Answer 33

1918-1920
H1N1
50 million deaths

Question 34

Asian flu

Answer 34

1957-58
H2N2
1-4 million deaths

Question 35

Hong kong flu

Answer 35

1968-69
H3N2
33,000 deaths

Question 36

Swine flu

Answer 36

2009-2010
New H1N1
19,000 deaths

Question 37

Bird flu/avian flu

Answer 37

H7N9

Question 38

Types of upper RTI’s

Answer 38

Common cold, Sinusitis, Tonsillitis and Laryngitis

Question 39

Types of lower RTI’s

Answer 39

Bronchitis, Bronchiolitis, Chest infection and Pneumoniae

Question 40

FeverPAIN scores

Answer 40

Determines if someone has Strep Pharyngitis. Score 1 point for each:
FEVER over 38 degrees
Purulence (pharyngeal / tonsillitis exudate)
Attend rapidly (3 days or less)
Severely inflamed tonsils
No cough or coryza